Pipe mould



June 27, 1967 LATOUR 3,327,769

PIPE MOULD Filed April 29, 1965 FIG. I

FIG. 2

INVENTOR LEOPOLD LATOUR ATTORNEYS United States Patent 3,327,769 PIPE MOULD Leopold Latour, Trois-Rivieres, Quebec, Canada, assrgnor to Canada Iron Foundries Limited, Montreal, Quebec, Canada Filed Apr. 29, 1965, Ser. No. 451,830 3 Claims. (Cl. 164-286) This invention relates to the manufacture of pipe by centrifugal casting. More particularly, the invention is concerned with the moulds used in such manufacture and with means for preventing poured metal from flowing out the ends of such moulds.

Centrifugal casting pipe moulds essentially consist of elongated tubes mounted for and adapted to be rotated. In casting pipe, molten metal is poured in one end of the mould as the latter is rotated, whereby the molten metal is thrown outwardly against the mould. Following setting of the metal, the cast pipe is extracted from the mould.

It is usual to provide stop off rings at both ends of the mould as to prevent metal from flowing out the ends. The stop off ring at the end from which the cast pipe is pulled is removable, while the stop ring at the end through which the metal is poured is normally fixed by being press fitted in the mould, bolted or permanently held in position by welding.

Experience with stop off rings described above has shown that failure of the moulds normally begins by scores created as the cast pipe is extracted from the mould, due to the presence of fins developed on the ends of the cast pipe. The fins are caused by the entry of metal into the joint between the end of the mould and the stop off ring located at the end through which the metal is poured. Even in the case of stop off rings which are welded on the pipe mould with weld material on the inside, it has been found that the weld material eventually breaks down, thereby causing poured metal to enter into fissures in the weld material, and resulting in fins on the ends of the cast pipe.

In accord with the present invention, the above described difiiculty is avoided by providing means for preventing metal from flowing out the end of the mould, particularly the end through which the metal is poured, which means includes, in combination with a stop off ring, an integral lip on the end of the pipe mould wall, which li-p is deformed inwardly whereby the line of contact between the lip and the stop off ring is located inwardly of the normal inner surface of the mould. With this means, any fins developed on the cast pipe by entry of metal into the joint between the lip and the stop off ring, will not score the inside surface of the mould as the cast pipe is removed. Such fins are located within the confines of the normal outer diameter of the pipe, and will not touch the inner surface of the mould as the cast pipe is removed.

The invention will be more thoroughly understood from the following description of preferred embodiments thereof as read in conjunction with the accompanying drawings.

In the drawings illustrating these embodiments of the invention:

FIGURE 1 is a cross-sectional view through one end of a pipe mould having means, in accord with a first embodiment of this invention, for preventing metal from flowing out of the end, and

FIGURE 2 is a similar view showing a preferred second embodiment of the invention.

Referring to FIGURE 1, the illustrated end of pipe mould is the end through which the molten metal is poured. For this purpose, the illustrated stop off ring 12 is centrally apertured. The outer surface of the mould wall carries an integral bearing flange 14 which cooper- 3,327,769 Patented June 27, 1967 ates with the mechanism, not shown in the drawings, for rotating the mould. It is also to be noted that such centrifugal casting pipe moulds arenormally formed of steel.

In accord with the present invention, the pipe mould is provided with an integral lip 16, which is deformed inwardly so that the line of contact, accessible to molten metal between the lip and stop off ring 12, is located inwardly of the normal inner surface 18 of the pipe mould. This line of contact is indicated by the reference numeral 20. Thus, any fins developed on the end of the cast pipe due to the entry of metal into the joint between lip 16 and stop off ring 12 at this line of contact 20 will not score the inner surface 18 of the pipe mould as the cast pipe is removed from the mould.

The integral portion of the pipe mould wall which forms lip 16 is demarked from the body of the mould wall by the removal of wall material shown in FIGURE 1 as an annular cavity which is subsequently filled with weld material 22. Following the removal of this wall material, lip 16 is inwardly deformed to develop the form of lip shown in FIGURE 1. After this inward deformation of lip 16 is completed, stop off ring 12 is welded to the end of the mould with the stop off ring abutting lip 16. The weld material 22 used to fix the stop off ring is provided in sufficient quantity to fill the annular cavity machined in the pipe mould end to demark lip 16.

Referring now to FIGURE 2, the illustrated second preferred embodiment of the invention differs from the first embodiment described above primarily in the use of a somewhat different stop off ring, and in the manner in which a portion of the stop off ring is combined with a portion of the weld material holding the stop off ring in place to form a bearing flange on the outer wall of the mould.

In the FIGURE 2 embodiment of the invention, lip 16 is also demarked as an integral portion of the wall by the removal of wall material. In this case, a portion of the outer surface of the mould wall is removed, which portion commences at the end of the mould and terminates at distance from this end, which defines the longitudinal dimension of lip 16. In attaching stop off ring 30 to the end of the mould, the weld material 32 fills the space formerly occupied by this removed wall material. Additional weld material is provided so that a portion thereof can be combined with a portion of the stop off ring to form the integral lug 34.

In-the two illustrated embodiments of the invention the stop off rings 12 and 30 are both shown as being welded to the end of mould 10. However, it will be appreciated that should it be desirable to fix the stop olf ring to the mould by bolts or by a press fit, it would still be possible to use an integral lip in cooperation with such a stop off ring. It is the use of this integral lip which avoids any joint or any weld material which could result in fins on the cast pipe capable of scoring the inner surface of the mould when the pipe is removed therefrom.

What I claim as my invention is:

1. In a centrifugal casting pipe mould essentially consisting of a rotatable tube, means preventing poured metal from flowing out of the end of said tube, said means comprising an annular lip on said end of the tube and a stop off ring carried at said end in abutting juxtaposition with said lip, said lip consisting of an integral portion of the wall of said tube which is deformed inwardly whereby the line of contact between said lip and said stop ofi? ring which is accessible to poured metal is located inwardly of the normal inner surface of the mould.

2. In a centrifugal casting pipe mould essentially consisting of a rotatable tube having an integral bearing flange on its outer surface adjacent one end, means presenting poured metal from flowing out said end of the tube, said means comprising an annular lip on said end of the tube and a stop off ring carried at said end in abutting juxtaposition with said lip, said lip consisting of an integral portion of the wall of said tube, which integral portion is demarked from the wall by the removal of wall material between said portion and the radially inner end of said flange, said lip being deformed inwardly whereby the line of contact between said lip and said stop off ring which is accessible to poured metal is located inwardly of the normal inner surface of the mould, said stop off ring being welded in its juxtaposed position with said lip with the Weld material filling the annular cavity in said wall end demarking said integral lip as to reinforce the mould wall in the region of said bearing flange.

3. In a centrifugal casting pipe mould essentially consisting of a rotatable tube having an integral bearing flange on its outer surface adjacent one end, means for preventing poured metal from flowing out said end of the tube, said means comprising an annular lip on said end of the tube and a stop off ring carried at said end in abutting juxtaposition with said lip, said lip consisting of an integral portion of the wall of said tube, which integral portion is demarked from the wall by the removal of wall material from the outer surface of the mould wall from the end of the wall towards the opposite end of the tube a predetermined distance defining the longitudinal dimension of said lip, said lip being deformed inwardly whereby the line of contact between said lip and said stop off ring which is accessible to poured metal is located inwardly of the normal inner surface of the mould, sad stop off ring being Welded in its juxtaposed position with said lip with the weld material filling the annular cavity in said wall demarking said integral lip, a portion of said weld material being shaped to form said bearing flange in conjunction with a portion of said stop off ring.

References Cited UNITED STATES PATENTS 1,498,138 6/1924 Wilder Q 22-1135 V. K. RISING, Assistant Examiner. 

1. IN A CENTRIFUGAL CASTING PIPE MOULD ESSENTIALLY CONSISTING OF A ROTATABLE TUBE, MEANS PREVENTING POURED METAL FROM FLOWING OUT OF THE END OF SAID TUBE, SAID MEANS COMPRISING AN ANNULAR LIP ON SAID END OF THE TUBE AND A STOP OFF RING CARRIED AT SAID END IN ABUTTING JUXTAPOSITION WITH SAID LIP, SAID LIP CONSISTING OF AN INTEGRAL PORTION OF THE WALL OF SAID TUBE WHICH IS DEFORMED INWARDLY WHEREBY THE LINE OF CONTACT BETWEEN SAID LIP AND SAID STOP OFF RING WHICH IS ACCESSIBLE TO POURED METAL IS LOCATED INWARDLY OF THE NORMAL INNER SURFACE OF THE MOULD. 